temperature and precipitation were calculated for each year up to 

 and including the spring when demography data were collected 

 (data from National Oceanic and Atmospheric Administration) . 

 Take 1991 for example, summer included June, July and August, 

 1990; fall included September, October and November, 1990; winter 

 included December, 1990 and January and February, 1991; and 

 spring included March, April and May, 1991. Entries for each 

 site and each year were used in the analyses. These analyses have 

 small sample sizes, and the results must be viewed as tentative. 



I also used correlation analysis to explore the 

 relationships between the proportions of aborted, predated and 

 fecund inflorescences and the total number of inflorescences 

 produced. In order to use both sites in the same analysis, I 

 relativized the variables at each site to the site means. 

 Probability values were not corrected for multiple tests. 



I surveyed a large Astragalus scaphoides population at 

 Hayden Creek, Idaho in late May, 1990 for inflorescence 

 predators. Insects observed girdling stems were collected and 

 sent to the Montana State Entomology Lab in Bozeman for 

 identification. 



RESULTS 



Population Growth 



The number of Astragalus scaphoides plants in the monitoring 

 transects increased in 1987-91 at both sites (Fig. 1). The 

 increase was small at Haynes Creek but more appreciable at Sheep 

 Corral Gulch. At both sites population growth rate was negative 

 in only one year out of four (Fig. 2): 1988 at Sheep Corral Gulch 

 and 1990 at Haynes Creek. In 1988 the Haynes Creek population 

 displayed the highest population growth, while the Sheep Corral 

 Gulch population had its lowest growth during the recording 

 period. Trends in population growth were similar at the two 

 sites for the other three years of the study (Fig. 2) . 



Survivorship 



Survivorship curves of the 1985 uneven-age Astragalus 

 scaphoides cohort were similar in shape for the two populations 

 (Fig. 3) . Mortality was higher during the first 1-2 years and 

 then leveled off to a gradual, even rate. The Haynes Creek 

 survivorship curve is steeper than at Sheep Corral Gulch, and 

 this difference is significant (log-rank test; LR=5.45, P=0.02). 

 The curves suggest that the majority of A^ scaphoides plants live 

 to be greater than six years old. 



Mortality rate ranged from 5-22% at the two sites and was 

 somewhat higher at Haynes Creek when all four years are taken 

 together (Fig. 4) . However, the temporal pattern of mortality 



